Caries begins with the adhesion of tooth decay bacteria, such as Streptococcus mutans, to the tooth surface for the formation of dental plaque, and organic acids produced by food metabolism by the tooth decay bacteria in the dental plaque demineralize dental enamel to cause an incipient caries condition. Saliva remineralizes the demineralized part through the action of calcium and phosphorous in the saliva and thereby serves to return the tooth to the original condition. If the remineralization can sufficiently regenerate the demineralized tooth, the occurrence of caries can be suppressed.
Accordingly, dentifrices containing a fluoride, or hydroxyapatite, one of calcium phosphates, having a crystal structure similar to the inorganic component of tooth, to promote the remineralization of the tooth are manufactured and distributed.
However, the saliva or the use a dentifrice containing a fluoride or hydroxyapatite is not sufficient for the remineralization of the demineralized part, and there is a need for the development of oral compositions, such as a dentifrice, capable of sufficiently achieving the remineralization.
Accordingly, there are proposed an oral dentifrice containing hydroxyapatite or tricalcium phosphate having a particle diameter of 0.05 μm to 1.0 μm which is capable of repairing minute asperities on the tooth surface, protecting the tooth surface, preventing tooth decay, strengthening dentin, and having an enhanced whitening effect (Patent Document 1), an oral composition capable of allowing hydroxyapatite fine powder to long reside on the tooth surface by the incorporation of the hydroxyapatite fine powder in a water-soluble cellulose solution (Patent Document 2), an oral composition capable of remarkably promoting remineralization through the combined use of a sugar alcohol, such as xylitol, and dibasic calcium phosphate (Patent Document 3), an oral composition containing low-crystallinity hydroxyapatite which is capable of preventing disease and unpleasant feelings in oral cavity by adhering to oral bacteria for bacteria elimination (Patent Document 4), an oral composition containing a calcium compound, such as hydroxyapatite, in royal jelly or its extract which is capable of whitening teeth, preventing tooth decay through remineralization, and preventing periodontal disease (Patent Document 5), a tooth-cleaning composition containing a calcium compound, such as hydroxyapatite, in an ultramarine composition which is capable of having a promoted tooth-remineralizing effect (Patent Document 6), a remineralization promoter having an anti-caries function, containing a micellar calcium phosphate-phosphopeptide complex (Patent Document 7), a method capable of promoting remineralization and suppressing caries by washing teeth using a dentifrice containing fluoride ions and then allowing an oral liquid composition containing calcium ions to act thereon (Patent Document 8), a tooth-cleaning composition having a pH of 5 to 8 and containing tricalcium phosphate as a powdered calcium salt having the ability to convert to hydroxyapatite by contacting with water in oral cavity (Patent Document 9), and the like.
To promote remineralization, a chewing gum and the like containing xylitol, and calcium phosphate, noncrystalline calcium phosphate, or calcium phosphoryl oligosaccharide are also manufactured; however, they are not necessarily sufficient in remineralization.
On the other hand, there are proposed tooth-cleaning compositions capable of imparting gloss to teeth by containing wax (Patent Documents 10 and 11), a method for improving the astringency of an oral composition containing an astringent compound (Patent Document 12), a method for suppressing the occurrence of astringency and metallic taste by incorporating wax in a tooth-cleaning composition having astringency and metallic taste (Patent Document 13), and the like. Wax is present on the surface of animal and plant bodies, often acts as a protective coat, and is used for grazing in cosmetics and pharmaceutical products and the like after purification; however, it has no tooth-remineralizing action.